lib/librte_eal/linuxapp/kni/kni_misc.c

   1 /*-
   2  * GPL LICENSE SUMMARY
   3  *
   4  *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of version 2 of the GNU General Public License as
   8  *   published by the Free Software Foundation.
   9  *
  10  *   This program is distributed in the hope that it will be useful, but
  11  *   WITHOUT ANY WARRANTY; without even the implied warranty of
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  *   General Public License for more details.
  14  *
  15  *   You should have received a copy of the GNU General Public License
  16  *   along with this program; if not, write to the Free Software
  17  *   Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
  18  *   The full GNU General Public License is included in this distribution
  19  *   in the file called LICENSE.GPL.
  20  *
  21  *   Contact Information:
  22  *   Intel Corporation
  23  */
  24
  25 #include <linux/version.h>
  26 #include <linux/module.h>
  27 #include <linux/miscdevice.h>
  28 #include <linux/netdevice.h>
  29 #include <linux/etherdevice.h>
  30 #include <linux/pci.h>
  31 #include <linux/kthread.h>
  32 #include <linux/rwsem.h>
  33 #include <linux/mutex.h>
  34 #include <linux/nsproxy.h>
  35 #include <net/net_namespace.h>
  36 #include <net/netns/generic.h>
  37
  38 #include <exec-env/rte_kni_common.h>
  39
  40 #include "compat.h"
  41 #include "kni_dev.h"
  42
  43 MODULE_LICENSE("Dual BSD/GPL");
  44 MODULE_AUTHOR("Intel Corporation");
  45 MODULE_DESCRIPTION("Kernel Module for managing kni devices");
  46
  47 #define KNI_RX_LOOP_NUM 1000
  48
  49 #define KNI_MAX_DEVICES 32
  50
  51 extern const struct pci_device_id ixgbe_pci_tbl[];
  52 extern const struct pci_device_id igb_pci_tbl[];
  53
  54 /* loopback mode */
  55 static char *lo_mode;
  56
  57 /* Kernel thread mode */
  58 static char *kthread_mode;
  59 static uint32_t multiple_kthread_on;
  60
  61 #define KNI_DEV_IN_USE_BIT_NUM 0 /* Bit number for device in use */
  62
  63 static int kni_net_id;
  64
  65 struct kni_net {
  66         unsigned long device_in_use; /* device in use flag */
  67         struct mutex kni_kthread_lock;
  68         struct task_struct *kni_kthread;
  69         struct rw_semaphore kni_list_lock;
  70         struct list_head kni_list_head;
  71 };
  72
  73 static int __net_init
  74 kni_init_net(struct net *net)
  75 {
  76 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
  77         struct kni_net *knet = net_generic(net, kni_net_id);
  78
  79         memset(knet, 0, sizeof(*knet));
  80 #else
  81         struct kni_net *knet;
  82         int ret;
  83
  84         knet = kzalloc(sizeof(struct kni_net), GFP_KERNEL);
  85         if (!knet) {
  86                 ret = -ENOMEM;
  87                 return ret;
  88         }
  89 #endif
  90
  91         /* Clear the bit of device in use */
  92         clear_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use);
  93
  94         mutex_init(&knet->kni_kthread_lock);
  95
  96         init_rwsem(&knet->kni_list_lock);
  97         INIT_LIST_HEAD(&knet->kni_list_head);
  98
  99 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 100         return 0;
 101 #else
 102         ret = net_assign_generic(net, kni_net_id, knet);
 103         if (ret < 0)
 104                 kfree(knet);
 105
 106         return ret;
 107 #endif
 108 }
 109
 110 static void __net_exit
 111 kni_exit_net(struct net *net)
 112 {
 113         struct kni_net *knet __maybe_unused;
 114
 115         knet = net_generic(net, kni_net_id);
 116         mutex_destroy(&knet->kni_kthread_lock);
 117
 118 #ifndef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 119         kfree(knet);
 120 #endif
 121 }
 122
 123 static struct pernet_operations kni_net_ops = {
 124         .init = kni_init_net,
 125         .exit = kni_exit_net,
 126 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 127         .id   = &kni_net_id,
 128         .size = sizeof(struct kni_net),
 129 #endif
 130 };
 131
 132 static int
 133 kni_thread_single(void *data)
 134 {
 135         struct kni_net *knet = data;
 136         int j;
 137         struct kni_dev *dev;
 138
 139         while (!kthread_should_stop()) {
 140                 down_read(&knet->kni_list_lock);
 141                 for (j = 0; j < KNI_RX_LOOP_NUM; j++) {
 142                         list_for_each_entry(dev, &knet->kni_list_head, list) {
 143                                 kni_net_rx(dev);
 144                                 kni_net_poll_resp(dev);
 145                         }
 146                 }
 147                 up_read(&knet->kni_list_lock);
 148 #ifdef RTE_KNI_PREEMPT_DEFAULT
 149                 /* reschedule out for a while */
 150                 schedule_timeout_interruptible(
 151                         usecs_to_jiffies(KNI_KTHREAD_RESCHEDULE_INTERVAL));
 152 #endif
 153         }
 154
 155         return 0;
 156 }
 157
 158 static int
 159 kni_thread_multiple(void *param)
 160 {
 161         int j;
 162         struct kni_dev *dev = param;
 163
 164         while (!kthread_should_stop()) {
 165                 for (j = 0; j < KNI_RX_LOOP_NUM; j++) {
 166                         kni_net_rx(dev);
 167                         kni_net_poll_resp(dev);
 168                 }
 169 #ifdef RTE_KNI_PREEMPT_DEFAULT
 170                 schedule_timeout_interruptible(
 171                         usecs_to_jiffies(KNI_KTHREAD_RESCHEDULE_INTERVAL));
 172 #endif
 173         }
 174
 175         return 0;
 176 }
 177
 178 static int
 179 kni_open(struct inode *inode, struct file *file)
 180 {
 181         struct net *net = current->nsproxy->net_ns;
 182         struct kni_net *knet = net_generic(net, kni_net_id);
 183
 184         /* kni device can be opened by one user only per netns */
 185         if (test_and_set_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use))
 186                 return -EBUSY;
 187
 188         file->private_data = get_net(net);
 189         pr_debug("/dev/kni opened\n");
 190
 191         return 0;
 192 }
 193
 194 static int
 195 kni_dev_remove(struct kni_dev *dev)
 196 {
 197         if (!dev)
 198                 return -ENODEV;
 199
 200 #ifdef RTE_KNI_KMOD_ETHTOOL
 201         if (dev->pci_dev) {
 202                 if (pci_match_id(ixgbe_pci_tbl, dev->pci_dev))
 203                         ixgbe_kni_remove(dev->pci_dev);
 204                 else if (pci_match_id(igb_pci_tbl, dev->pci_dev))
 205                         igb_kni_remove(dev->pci_dev);
 206         }
 207 #endif
 208
 209         if (dev->net_dev) {
 210                 unregister_netdev(dev->net_dev);
 211                 free_netdev(dev->net_dev);
 212         }
 213
 214         return 0;
 215 }
 216
 217 static int
 218 kni_release(struct inode *inode, struct file *file)
 219 {
 220         struct net *net = file->private_data;
 221         struct kni_net *knet = net_generic(net, kni_net_id);
 222         struct kni_dev *dev, *n;
 223
 224         /* Stop kernel thread for single mode */
 225         if (multiple_kthread_on == 0) {
 226                 mutex_lock(&knet->kni_kthread_lock);
 227                 /* Stop kernel thread */
 228                 if (knet->kni_kthread != NULL) {
 229                         kthread_stop(knet->kni_kthread);
 230                         knet->kni_kthread = NULL;
 231                 }
 232                 mutex_unlock(&knet->kni_kthread_lock);
 233         }
 234
 235         down_write(&knet->kni_list_lock);
 236         list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
 237                 /* Stop kernel thread for multiple mode */
 238                 if (multiple_kthread_on && dev->pthread != NULL) {
 239                         kthread_stop(dev->pthread);
 240                         dev->pthread = NULL;
 241                 }
 242
 243                 kni_dev_remove(dev);
 244                 list_del(&dev->list);
 245         }
 246         up_write(&knet->kni_list_lock);
 247
 248         /* Clear the bit of device in use */
 249         clear_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use);
 250
 251         put_net(net);
 252         pr_debug("/dev/kni closed\n");
 253
 254         return 0;
 255 }
 256
 257 static int
 258 kni_check_param(struct kni_dev *kni, struct rte_kni_device_info *dev)
 259 {
 260         if (!kni || !dev)
 261                 return -1;
 262
 263         /* Check if network name has been used */
 264         if (!strncmp(kni->name, dev->name, RTE_KNI_NAMESIZE)) {
 265                 pr_err("KNI name %s duplicated\n", dev->name);
 266                 return -1;
 267         }
 268
 269         return 0;
 270 }
 271
 272 static int
 273 kni_run_thread(struct kni_net *knet, struct kni_dev *kni, uint8_t force_bind)
 274 {
 275         /**
 276          * Create a new kernel thread for multiple mode, set its core affinity,
 277          * and finally wake it up.
 278          */
 279         if (multiple_kthread_on) {
 280                 kni->pthread = kthread_create(kni_thread_multiple,
 281                         (void *)kni, "kni_%s", kni->name);
 282                 if (IS_ERR(kni->pthread)) {
 283                         kni_dev_remove(kni);
 284                         return -ECANCELED;
 285                 }
 286
 287                 if (force_bind)
 288                         kthread_bind(kni->pthread, kni->core_id);
 289                 wake_up_process(kni->pthread);
 290         } else {
 291                 mutex_lock(&knet->kni_kthread_lock);
 292
 293                 if (knet->kni_kthread == NULL) {
 294                         knet->kni_kthread = kthread_create(kni_thread_single,
 295                                 (void *)knet, "kni_single");
 296                         if (IS_ERR(knet->kni_kthread)) {
 297                                 mutex_unlock(&knet->kni_kthread_lock);
 298                                 kni_dev_remove(kni);
 299                                 return -ECANCELED;
 300                         }
 301
 302                         if (force_bind)
 303                                 kthread_bind(knet->kni_kthread, kni->core_id);
 304                         wake_up_process(knet->kni_kthread);
 305                 }
 306
 307                 mutex_unlock(&knet->kni_kthread_lock);
 308         }
 309
 310         return 0;
 311 }
 312
 313 static int
 314 kni_ioctl_create(struct net *net, uint32_t ioctl_num,
 315                 unsigned long ioctl_param)
 316 {
 317         struct kni_net *knet = net_generic(net, kni_net_id);
 318         int ret;
 319         struct rte_kni_device_info dev_info;
 320         struct net_device *net_dev = NULL;
 321         struct kni_dev *kni, *dev, *n;
 322 #ifdef RTE_KNI_KMOD_ETHTOOL
 323         struct pci_dev *found_pci = NULL;
 324         struct net_device *lad_dev = NULL;
 325         struct pci_dev *pci = NULL;
 326 #endif
 327
 328         pr_info("Creating kni...\n");
 329         /* Check the buffer size, to avoid warning */
 330         if (_IOC_SIZE(ioctl_num) > sizeof(dev_info))
 331                 return -EINVAL;
 332
 333         /* Copy kni info from user space */
 334         ret = copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info));
 335         if (ret) {
 336                 pr_err("copy_from_user in kni_ioctl_create");
 337                 return -EIO;
 338         }
 339
 340         /* Check if name is zero-ended */
 341         if (strnlen(dev_info.name, sizeof(dev_info.name)) == sizeof(dev_info.name)) {
 342                 pr_err("kni.name not zero-terminated");
 343                 return -EINVAL;
 344         }
 345
 346         /**
 347          * Check if the cpu core id is valid for binding.
 348          */
 349         if (dev_info.force_bind && !cpu_online(dev_info.core_id)) {
 350                 pr_err("cpu %u is not online\n", dev_info.core_id);
 351                 return -EINVAL;
 352         }
 353
 354         /* Check if it has been created */
 355         down_read(&knet->kni_list_lock);
 356         list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
 357                 if (kni_check_param(dev, &dev_info) < 0) {
 358                         up_read(&knet->kni_list_lock);
 359                         return -EINVAL;
 360                 }
 361         }
 362         up_read(&knet->kni_list_lock);
 363
 364         net_dev = alloc_netdev(sizeof(struct kni_dev), dev_info.name,
 365 #ifdef NET_NAME_USER
 366                                                         NET_NAME_USER,
 367 #endif
 368                                                         kni_net_init);
 369         if (net_dev == NULL) {
 370                 pr_err("error allocating device \"%s\"\n", dev_info.name);
 371                 return -EBUSY;
 372         }
 373
 374         dev_net_set(net_dev, net);
 375
 376         kni = netdev_priv(net_dev);
 377
 378         kni->net_dev = net_dev;
 379         kni->group_id = dev_info.group_id;
 380         kni->core_id = dev_info.core_id;
 381         strncpy(kni->name, dev_info.name, RTE_KNI_NAMESIZE);
 382
 383         /* Translate user space info into kernel space info */
 384         kni->tx_q = phys_to_virt(dev_info.tx_phys);
 385         kni->rx_q = phys_to_virt(dev_info.rx_phys);
 386         kni->alloc_q = phys_to_virt(dev_info.alloc_phys);
 387         kni->free_q = phys_to_virt(dev_info.free_phys);
 388
 389         kni->req_q = phys_to_virt(dev_info.req_phys);
 390         kni->resp_q = phys_to_virt(dev_info.resp_phys);
 391         kni->sync_va = dev_info.sync_va;
 392         kni->sync_kva = phys_to_virt(dev_info.sync_phys);
 393
 394         kni->mbuf_size = dev_info.mbuf_size;
 395
 396         pr_debug("tx_phys:      0x%016llx, tx_q addr:      0x%p\n",
 397                 (unsigned long long) dev_info.tx_phys, kni->tx_q);
 398         pr_debug("rx_phys:      0x%016llx, rx_q addr:      0x%p\n",
 399                 (unsigned long long) dev_info.rx_phys, kni->rx_q);
 400         pr_debug("alloc_phys:   0x%016llx, alloc_q addr:   0x%p\n",
 401                 (unsigned long long) dev_info.alloc_phys, kni->alloc_q);
 402         pr_debug("free_phys:    0x%016llx, free_q addr:    0x%p\n",
 403                 (unsigned long long) dev_info.free_phys, kni->free_q);
 404         pr_debug("req_phys:     0x%016llx, req_q addr:     0x%p\n",
 405                 (unsigned long long) dev_info.req_phys, kni->req_q);
 406         pr_debug("resp_phys:    0x%016llx, resp_q addr:    0x%p\n",
 407                 (unsigned long long) dev_info.resp_phys, kni->resp_q);
 408         pr_debug("mbuf_size:    %u\n", kni->mbuf_size);
 409
 410         pr_debug("PCI: %02x:%02x.%02x %04x:%04x\n",
 411                                         dev_info.bus,
 412                                         dev_info.devid,
 413                                         dev_info.function,
 414                                         dev_info.vendor_id,
 415                                         dev_info.device_id);
 416 #ifdef RTE_KNI_KMOD_ETHTOOL
 417         pci = pci_get_device(dev_info.vendor_id, dev_info.device_id, NULL);
 418
 419         /* Support Ethtool */
 420         while (pci) {
 421                 pr_debug("pci_bus: %02x:%02x:%02x\n",
 422                                         pci->bus->number,
 423                                         PCI_SLOT(pci->devfn),
 424                                         PCI_FUNC(pci->devfn));
 425
 426                 if ((pci->bus->number == dev_info.bus) &&
 427                         (PCI_SLOT(pci->devfn) == dev_info.devid) &&
 428                         (PCI_FUNC(pci->devfn) == dev_info.function)) {
 429                         found_pci = pci;
 430
 431                         if (pci_match_id(ixgbe_pci_tbl, found_pci))
 432                                 ret = ixgbe_kni_probe(found_pci, &lad_dev);
 433                         else if (pci_match_id(igb_pci_tbl, found_pci))
 434                                 ret = igb_kni_probe(found_pci, &lad_dev);
 435                         else
 436                                 ret = -1;
 437
 438                         pr_debug("PCI found: pci=0x%p, lad_dev=0x%p\n",
 439                                                         pci, lad_dev);
 440                         if (ret == 0) {
 441                                 kni->lad_dev = lad_dev;
 442                                 kni_set_ethtool_ops(kni->net_dev);
 443                         } else {
 444                                 pr_err("Device not supported by ethtool");
 445                                 kni->lad_dev = NULL;
 446                         }
 447
 448                         kni->pci_dev = found_pci;
 449                         kni->device_id = dev_info.device_id;
 450                         break;
 451                 }
 452                 pci = pci_get_device(dev_info.vendor_id,
 453                                 dev_info.device_id, pci);
 454         }
 455         if (pci)
 456                 pci_dev_put(pci);
 457 #endif
 458
 459         if (kni->lad_dev)
 460                 ether_addr_copy(net_dev->dev_addr, kni->lad_dev->dev_addr);
 461         else
 462                 /*
 463                  * Generate random mac address. eth_random_addr() is the newer
 464                  * version of generating mac address in linux kernel.
 465                  */
 466                 random_ether_addr(net_dev->dev_addr);
 467
 468         ret = register_netdev(net_dev);
 469         if (ret) {
 470                 pr_err("error %i registering device \"%s\"\n",
 471                                         ret, dev_info.name);
 472                 kni->net_dev = NULL;
 473                 kni_dev_remove(kni);
 474                 free_netdev(net_dev);
 475                 return -ENODEV;
 476         }
 477
 478         ret = kni_run_thread(knet, kni, dev_info.force_bind);
 479         if (ret != 0)
 480                 return ret;
 481
 482         down_write(&knet->kni_list_lock);
 483         list_add(&kni->list, &knet->kni_list_head);
 484         up_write(&knet->kni_list_lock);
 485
 486         return 0;
 487 }
 488
 489 static int
 490 kni_ioctl_release(struct net *net, uint32_t ioctl_num,
 491                 unsigned long ioctl_param)
 492 {
 493         struct kni_net *knet = net_generic(net, kni_net_id);
 494         int ret = -EINVAL;
 495         struct kni_dev *dev, *n;
 496         struct rte_kni_device_info dev_info;
 497
 498         if (_IOC_SIZE(ioctl_num) > sizeof(dev_info))
 499                 return -EINVAL;
 500
 501         ret = copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info));
 502         if (ret) {
 503                 pr_err("copy_from_user in kni_ioctl_release");
 504                 return -EIO;
 505         }
 506
 507         /* Release the network device according to its name */
 508         if (strlen(dev_info.name) == 0)
 509                 return ret;
 510
 511         down_write(&knet->kni_list_lock);
 512         list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
 513                 if (strncmp(dev->name, dev_info.name, RTE_KNI_NAMESIZE) != 0)
 514                         continue;
 515
 516                 if (multiple_kthread_on && dev->pthread != NULL) {
 517                         kthread_stop(dev->pthread);
 518                         dev->pthread = NULL;
 519                 }
 520
 521                 kni_dev_remove(dev);
 522                 list_del(&dev->list);
 523                 ret = 0;
 524                 break;
 525         }
 526         up_write(&knet->kni_list_lock);
 527         pr_info("%s release kni named %s\n",
 528                 (ret == 0 ? "Successfully" : "Unsuccessfully"), dev_info.name);
 529
 530         return ret;
 531 }
 532
 533 static int
 534 kni_ioctl(struct inode *inode, uint32_t ioctl_num, unsigned long ioctl_param)
 535 {
 536         int ret = -EINVAL;
 537         struct net *net = current->nsproxy->net_ns;
 538
 539         pr_debug("IOCTL num=0x%0x param=0x%0lx\n", ioctl_num, ioctl_param);
 540
 541         /*
 542          * Switch according to the ioctl called
 543          */
 544         switch (_IOC_NR(ioctl_num)) {
 545         case _IOC_NR(RTE_KNI_IOCTL_TEST):
 546                 /* For test only, not used */
 547                 break;
 548         case _IOC_NR(RTE_KNI_IOCTL_CREATE):
 549                 ret = kni_ioctl_create(net, ioctl_num, ioctl_param);
 550                 break;
 551         case _IOC_NR(RTE_KNI_IOCTL_RELEASE):
 552                 ret = kni_ioctl_release(net, ioctl_num, ioctl_param);
 553                 break;
 554         default:
 555                 pr_debug("IOCTL default\n");
 556                 break;
 557         }
 558
 559         return ret;
 560 }
 561
 562 static int
 563 kni_compat_ioctl(struct inode *inode, uint32_t ioctl_num,
 564                 unsigned long ioctl_param)
 565 {
 566         /* 32 bits app on 64 bits OS to be supported later */
 567         pr_debug("Not implemented.\n");
 568
 569         return -EINVAL;
 570 }
 571
 572 static const struct file_operations kni_fops = {
 573         .owner = THIS_MODULE,
 574         .open = kni_open,
 575         .release = kni_release,
 576         .unlocked_ioctl = (void *)kni_ioctl,
 577         .compat_ioctl = (void *)kni_compat_ioctl,
 578 };
 579
 580 static struct miscdevice kni_misc = {
 581         .minor = MISC_DYNAMIC_MINOR,
 582         .name = KNI_DEVICE,
 583         .fops = &kni_fops,
 584 };
 585
 586 static int __init
 587 kni_parse_kthread_mode(void)
 588 {
 589         if (!kthread_mode)
 590                 return 0;
 591
 592         if (strcmp(kthread_mode, "single") == 0)
 593                 return 0;
 594         else if (strcmp(kthread_mode, "multiple") == 0)
 595                 multiple_kthread_on = 1;
 596         else
 597                 return -1;
 598
 599         return 0;
 600 }
 601
 602 static int __init
 603 kni_init(void)
 604 {
 605         int rc;
 606
 607         if (kni_parse_kthread_mode() < 0) {
 608                 pr_err("Invalid parameter for kthread_mode\n");
 609                 return -EINVAL;
 610         }
 611
 612         if (multiple_kthread_on == 0)
 613                 pr_debug("Single kernel thread for all KNI devices\n");
 614         else
 615                 pr_debug("Multiple kernel thread mode enabled\n");
 616
 617 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 618         rc = register_pernet_subsys(&kni_net_ops);
 619 #else
 620         rc = register_pernet_gen_subsys(&kni_net_id, &kni_net_ops);
 621 #endif
 622         if (rc)
 623                 return -EPERM;
 624
 625         rc = misc_register(&kni_misc);
 626         if (rc != 0) {
 627                 pr_err("Misc registration failed\n");
 628                 goto out;
 629         }
 630
 631         /* Configure the lo mode according to the input parameter */
 632         kni_net_config_lo_mode(lo_mode);
 633
 634         return 0;
 635
 636 out:
 637 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 638         unregister_pernet_subsys(&kni_net_ops);
 639 #else
 640         unregister_pernet_gen_subsys(kni_net_id, &kni_net_ops);
 641 #endif
 642         return rc;
 643 }
 644
 645 static void __exit
 646 kni_exit(void)
 647 {
 648         misc_deregister(&kni_misc);
 649 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 650         unregister_pernet_subsys(&kni_net_ops);
 651 #else
 652         unregister_pernet_gen_subsys(kni_net_id, &kni_net_ops);
 653 #endif
 654 }
 655
 656 module_init(kni_init);
 657 module_exit(kni_exit);
 658
 659 module_param(lo_mode, charp, S_IRUGO | S_IWUSR);
 660 MODULE_PARM_DESC(lo_mode,
 661 "KNI loopback mode (default=lo_mode_none):\n"
 662 "    lo_mode_none        Kernel loopback disabled\n"
 663 "    lo_mode_fifo        Enable kernel loopback with fifo\n"
 664 "    lo_mode_fifo_skb    Enable kernel loopback with fifo and skb buffer\n"
 665 "\n"
 666 );
 667
 668 module_param(kthread_mode, charp, S_IRUGO);
 669 MODULE_PARM_DESC(kthread_mode,
 670 "Kernel thread mode (default=single):\n"
 671 "    single    Single kernel thread mode enabled.\n"
 672 "    multiple  Multiple kernel thread mode enabled.\n"
 673 "\n"
 674 );